Carburetor



June 21, 1938. V, R HEFTLER 2,120,975

CARBURETOR Filed Feb. 15, 1957 Cil Patented June 21, 1938 UNITED STATES PATENT OFFICEv cmmmroa Application February 15, 1937, Serial No. 125,707

2 Claims.

ceedingly cheap and simple yet durable and eiilcient carburetor.

Another object of the invention is to provide a miniature carburetor for small power plants having but few component parts so that its manufacture and assembly may be economically facilitated.

Another object of the invention isto provide a. carburetor associated with a conventional fuel tank in such a manner as to reduce re hazards.

Another object of the invention is to provide a carburetor in which the fluid in the fuel chamber maybe maintained at a constant level.

Yet a further object of the invention is to provide a carburetor including a float chamber submerged in a fuel tank and opening directly into the fuel tank. v

Other'objects and advantages of the invention Will appear from the following description taken in connection with the drawing forming a part of this specification and in which,

Fig. 1 is a side elevation of a fuel tank having a carburetor mounted in its top;

Fig. 2 is an enlarged view of the carburetor, partly in elevation and partly in section, associated with a fuel tank having parts broken away;

Fig. 3 is a sectional View substantially on line 3-3, Fig. 2;

Fig. 4 is a sectional view substantially on line 4 4, Fig. 3;

Fig. 5 is a sectional view of the float chamber takenl just back of the fuel delivery tube;

Fig. 6 is a sectional view of a modification o the oat chamber; and

Fig. '1 is a sectional view substantially on line 1-1, Fig. 6.

Referring to the drawing for more specic details of the invention, I6 represents a conventional fuel tank having a drain opening which may be closed as by a plug I2 and a filling opening which may be closed as by a cap I4. The tank also has in its top an opening which may be closed as by a cover 'plate I6 provided with a flange I8 detachably secured to the tank with a suitable gasket interposed for sealing purposes. This cover plate I6 supports a carburetor partly within and partly outside of the tank.

'I'he carburetor includes a base 22 clamped on the cover plate I6 as by screws 24 with a suitable gasket 26 interposed for sealing purposes and a body portion 28 formed normal to the base.

`A passage 30 vextending through the base and body portion has one of its ends registering with an opening in the cover plate as indicated at 32, and its other end internally threaded as at 34.

'I'he passage 30 has intermediate its length an annular boss 36 forming an orifice 38 which is controlled as by a needle 40 mounted for travel 5 in the threaded end 34 of the passage 30. A spring-pressed detent 42 mounted in a recess in the body portion cooperates with the serrated under surface of the head of needle 4I) for retaining the needle in adjusted position.

A Venturi tube 44 formed in the body portion 28 has a fuel suction inlet port 46 communicating with the passage 36 beyond the controlled orifice 38. 'I'he air intake end of the Venturi tube has diametrically disposed air inlet slots 48, and a. 15 cap fitted for rotation on the tube has slots 52 adapted to register with the slots 48 to serve as a choke valve. The cap is held against displacement as by a pin 54 in the Venturi tube receiving a slot 56 in the wall of the cap. By ro- 20 tating the cap 50 the air inlet may be regulated as desired. The discharge end of the venturi has formed thereon a clamp 58 for attaching a fuel delivery tube 60 connecting the Venturi tube to the manifold or intake port of a power plant, not 25 shown. A thimble 62 fitted snugly in thepassage 36 has a flange 64 suitably secured to the cover plate I6. This thimble receives and has fixedly secured thereto one end of a fuel delivery tube. 66, the other end of which extends into a float chamber 68 and communicates therewith adjacent the bottom of the chamber. A check valve 16 at the lower end of the tube prevents reverse flow of the fuel therein.

The float chamber is iixedly secured to the tube '35 66 and a vent tube 12 suitably secured in the top of the float chamber extends through and is permanently secured to the cover plate I6, the protruding end of the vent tube being deformed as at 14 to inhibit the intake of foreign substances. 40 The fuel delivery tube 66 and the vent tube 12 serve a double purpose in that they not only conduct fuel and air but also support the oat chamber in the fuel tank.

As shown; the float chamber is of such a size 45 that it may beeasily passed through the opening in the top of the tank.- The oat chamber is preferably suspended in the fuel tank adjacentv the bottom thereof and is provided in its bottom with an intake port 16 opening directly into the 50 tank and screened as indicated at 18, and the intake port is controlled as by a valve 80 actuated by a float 82.v v

A modification of the oat chamber is ill trated in Figs. 6 and '7. In this'modication a 55 oat chamber Illll is suspended in a fuel tank |02 from the body of the carburetor. As shown, a fluid delivery tube |04 and a vent tube |06, adapted to be secured to the body portion of the carburetor and the cover plate as in the preferred form of the invention, support the float chamber |00 in a sump |08 formed in the bottom of the fuel tank, and a bracket lili secured to the wall of the float chamber embraces the tubes.

The float chamber includes cylindrical cup sections ||2 and ||4 threaded together as indicated at IIB and an inverted perforated cup H8 mounted concentrically within the cup section' H2 providing a guide for a, spherical float |20. A sleeve |22 supported at one end .and closed at its other end is mounted concentrically in the inverted cup ||8 and extends upwardly through the cup section ||2 into the tank adjacent the bottom thereof, and the closed end of the sleeve -is provided with an oriilce I 24 controlled as by a pin |26 on the float |20.

AIn operation, suction created by the power plant draws air through the Venturi tube 44. This movement of air through the Venturi tube sucks fuel from the float chamber 68 past the check valve '10, through the fuel delivery tube 66 and the passage 30 past the needle 40, thence through the port 46 into the Venturi tube, where it is vaporized and conducted through the tube to the power plant.

Although this invention has been described in connection with certain specic embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is,-

1. A charge forming apparatus for an internal combustion engine, comprising a. fuel tank having an opening in its top, a covery plate for the opening, a carburetor fixed to the cover plate and provided with a horizontal Venturi passage, a float chamber located adjacent the bottom of the tank and having an inlet located adjacent the bottom of the tank, a liquid fuel conduit extending from the oat chamber to the carburetor, a vent conduit connecting the float chamber to atmosphere, said conduits being fixed to the cover plate and float chamber, and a check valve preventing return flow in the liquid fuel conduit.

2. A charge forming 'apparatus for an internal combustion engine comprising a fuel tank having an opening in its top, a cover plate for the openin'g, a. fuel lift carburetor xed to the cover plate and provided with a horizontal mixing passage, adjustable fuel and air inlets for the mixing passage, a fuel chamber positioned within the tank having an inlet located below the normal fuel level therein, means for maintaining the fuel level in the chamber constant, a liquid fuel conduit extending from the bottom portion of the fuel chamber to said fuel inlet and providedwith a check valve below the fuel level in the chamber, and a vent conduit extending from the float f chamber to atmosphere through the cover plate,

said conduits being fixed to the cover plate and float chamber. 

